[nvptx libgomp plugin] Build only in supported configurations

As recently again discussed in <https://gcc.gnu.org/PR97436> "[nvptx] -m32
support", nvptx offloading other than for 64-bit host has never been
implemented, tested, supported.  So we simply should buildn't the nvptx libgomp
plugin in this case.

This avoids build problems if, for example, in a (standard) bi-arch
x86_64-pc-linux-gnu '-m64'/'-m32' build, libcuda is available only in a 64-bit
variant but not in a 32-bit one, which, for example, is the case if you build
GCC against the CUDA toolkit's 'stubs/libcuda.so' (see
<https://stackoverflow.com/a/52784819>).

This amends PR65099 commit a92defdab79a1268f4b9dcf42b937e4002a4cf15 (r225560)
"[nvptx offloading] Only 64-bit configurations are currently supported" to
match the way we're doing this for the HSA/GCN plugins.

	libgomp/
	PR libgomp/65099
	* plugin/configfrag.ac (PLUGIN_NVPTX): Restrict to supported
	configurations.
	* configure: Regenerate.
	* plugin/plugin-nvptx.c (nvptx_get_num_devices): Remove 64-bit
	check.

1 files changed, 51 insertions, 35 deletions

diff --git a/libgomp/configure b/libgomp/configure
index 89c17c571b7..48bf8e4a72c 100755
--- a/libgomp/configure
+++ b/libgomp/configure
@@ -15272,21 +15272,30 @@ if test x"$enable_offload_targets" != x; then
 	tgt_plugin=intelmic
 	;;
       nvptx*)
-	tgt_plugin=nvptx
-	PLUGIN_NVPTX=$tgt
-	if test "x$CUDA_DRIVER_LIB" != xno \
-	   && test "x$CUDA_DRIVER_LIB" != xno; then
-	  PLUGIN_NVPTX_CPPFLAGS=$CUDA_DRIVER_CPPFLAGS
-	  PLUGIN_NVPTX_LDFLAGS=$CUDA_DRIVER_LDFLAGS
-	  PLUGIN_NVPTX_LIBS='-lcuda'
-
-	  PLUGIN_NVPTX_save_CPPFLAGS=$CPPFLAGS
-	  CPPFLAGS="$PLUGIN_NVPTX_CPPFLAGS $CPPFLAGS"
-	  PLUGIN_NVPTX_save_LDFLAGS=$LDFLAGS
-	  LDFLAGS="$PLUGIN_NVPTX_LDFLAGS $LDFLAGS"
-	  PLUGIN_NVPTX_save_LIBS=$LIBS
-	  LIBS="$PLUGIN_NVPTX_LIBS $LIBS"
-	  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+	case "${target}" in
+	  aarch64*-*-* | powerpc64le-*-* | x86_64-*-*)
+	    case " ${CC} ${CFLAGS} " in
+	      *" -m32 "* | *" -mx32 "*)
+		# PR libgomp/65099: Currently, we only support offloading in
+		# 64-bit configurations.
+		PLUGIN_NVPTX=0
+		;;
+	      *)
+		tgt_plugin=nvptx
+		PLUGIN_NVPTX=$tgt
+		if test "x$CUDA_DRIVER_LIB" != xno \
+		   && test "x$CUDA_DRIVER_LIB" != xno; then
+		  PLUGIN_NVPTX_CPPFLAGS=$CUDA_DRIVER_CPPFLAGS
+		  PLUGIN_NVPTX_LDFLAGS=$CUDA_DRIVER_LDFLAGS
+		  PLUGIN_NVPTX_LIBS='-lcuda'
+
+		  PLUGIN_NVPTX_save_CPPFLAGS=$CPPFLAGS
+		  CPPFLAGS="$PLUGIN_NVPTX_CPPFLAGS $CPPFLAGS"
+		  PLUGIN_NVPTX_save_LDFLAGS=$LDFLAGS
+		  LDFLAGS="$PLUGIN_NVPTX_LDFLAGS $LDFLAGS"
+		  PLUGIN_NVPTX_save_LIBS=$LIBS
+		  LIBS="$PLUGIN_NVPTX_LIBS $LIBS"
+		  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include "cuda.h"
 int
@@ -15302,28 +15311,35 @@ if ac_fn_c_try_link "$LINENO"; then :
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
-	  CPPFLAGS=$PLUGIN_NVPTX_save_CPPFLAGS
-	  LDFLAGS=$PLUGIN_NVPTX_save_LDFLAGS
-	  LIBS=$PLUGIN_NVPTX_save_LIBS
-	fi
-	case $PLUGIN_NVPTX in
-	  nvptx*)
-	    if (test "x$CUDA_DRIVER_INCLUDE" = x \
-		|| test "x$CUDA_DRIVER_INCLUDE" = xno) \
-	       && (test "x$CUDA_DRIVER_LIB" = x \
-		   || test "x$CUDA_DRIVER_LIB" = xno); then
-	      PLUGIN_NVPTX=1
-	      PLUGIN_NVPTX_CPPFLAGS='-I$(srcdir)/plugin/cuda'
-	      PLUGIN_NVPTX_LIBS='-ldl'
-	      PLUGIN_NVPTX_DYNAMIC=1
-	    else
-	      PLUGIN_NVPTX=0
-	      as_fn_error $? "CUDA driver package required for nvptx support" "$LINENO" 5
-	    fi
-	  ;;
+		  CPPFLAGS=$PLUGIN_NVPTX_save_CPPFLAGS
+		  LDFLAGS=$PLUGIN_NVPTX_save_LDFLAGS
+		  LIBS=$PLUGIN_NVPTX_save_LIBS
+		fi
+		case $PLUGIN_NVPTX in
+		  nvptx*)
+		    if (test "x$CUDA_DRIVER_INCLUDE" = x \
+			|| test "x$CUDA_DRIVER_INCLUDE" = xno) \
+		       && (test "x$CUDA_DRIVER_LIB" = x \
+			   || test "x$CUDA_DRIVER_LIB" = xno); then
+		      PLUGIN_NVPTX=1
+		      PLUGIN_NVPTX_CPPFLAGS='-I$(srcdir)/plugin/cuda'
+		      PLUGIN_NVPTX_LIBS='-ldl'
+		      PLUGIN_NVPTX_DYNAMIC=1
+		    else
+		      PLUGIN_NVPTX=0
+		      as_fn_error $? "CUDA driver package required for nvptx support" "$LINENO" 5
+		    fi
+		    ;;
+		esac
+		;;
+	    esac
+	    ;;
+	  *-*-*)
+	    # Target architecture not supported.
+	    PLUGIN_NVPTX=0
+	    ;;
 	esac
 	;;
-
       amdgcn*)
 	case "${target}" in
 	  x86_64-*-*)